Electric filament lamp

ABSTRACT

Copying lamps having a filament which is constructed from shorter and longer coil segments which are connected by intermediate members have the drawback that after recrystallisation the intermediate members with the ends of the longer segments have warped. This is avoided by supporting the longer segments at their ends.

Utte atet 11 1 1111 3,758,807

0 de Beeck 1451 Se 1. 11 1973 1 ELECTRIC FILAMENT LAMP 3,080,497 3/1963Noel et a1. 313 271 x [75] Inventor e bt Kamiel Maria 0, dc Beec3,295,007 12/1966 Young 313/273 Emmasingel, Eindhoven, NetherlandsPrimary Examiner-David Schonberg [73] Ass1gnee: U.S.Phi1ips Corporation,New York, Assistant p A Attorney-Frank R. Trifari [22] Filed:v Aug. 30,1971 [21] I Appl. No.: 175,867

57 ABSTRACT [30] Foreign Application Priority Data 1 Sept. 3, 1970Netherlands 7013030 I A Copymg lamps having a filament wh1ch 1sconstructed 52 .s.-c1. 313/273, 313/315, 313/317 and 9 Segments whichare 51 1111.0 1101; '1/92, H01] 19/46 "ected by q e members have Edrawback 58 Field of Search 313 271 273 279 that after recrysmlhsam" themtermed'ate members i J 3 with the ends of the longer segments havewarped. This is avoided by supporting the longer segments at their [56]References Cited P UNI-TED STATES PATENTS 2,712,089 1 Claim, 1 DrawingFigure 6/1955 Lamb 313/279 X i MW/77 PATENTEDSEPI 1 I975 31,58,807

7a 7a, 6 7d 6 7e s 7 7g 1.

INVENTOR HERBERT K. M. OP DE BEECK 2M E l/i AGENT ELECTRIC FILAMENT LAMPV The invention relates to an electric filament lamp having a tubularenvelope which is sealed by pinches and comprises a filament whichextends in the longitudinal direction of the lamp, said filamentconsisting of tral aperture in'which the relevant configuration ispresent, the outer circumference of said support bearing against theinside of the envelope. Such a filament lamp is known for reproductionpurposes. By means of this lamp the possibility is provided of uniformlyexposing a surface to be exposed.

In these known filament lamps, the supports which support-the longerconfigurations are present between the center and each of the ends ofsuch a configuration.

In order to give the material of the filament lamp a fibrous structure,the filament is subjected for a few seconds to a' current pluse by whichthe temperature increases due to the resistance, so that the materialrecrystallises. Because during this operation the filament should extendcoaxially in the lamp envelope, which in the case of a horizontalposition of the envelope is avoided due to the influence of gravity, thefilament is introduced into an electromagnetic field, so that thesagging as a result of gravityis compensated forl It has been found thatin the known filament lamps of this type in which the supports whichsupport the longer configurations are present between the center andeach of the ends of the configuration, the intermediate members with theends of the longer configurations present beside the supports havewarped after the recrystallisation process. It is the object of theinvention to avoid this drawback. For that purpose, an electric filamentlamp according to the invention is characterized in that the supportswhich are present between the supports adjoining the pinches and whichsupport the longer configurations are provided at the ends of therelevant configurations. As a result of this it is achieved that thelonger configurations remain extending coaxially with the lamp envelopethroughout their length during the recrystallisation process.

In order that the invention may be readily carried into effect, oneembodiment thereof will now be described in greater detail, by way ofexample, with reference to the accompanying diagrammatic drawing, thesole FIGURE of which shows one embodiment of a filament lamp accordingto the invention.

The filament lamp comprises a tubular lamp envelope 1 which is sealed atits ends by means of pinches 2. The filament 3 is secured in the pinchesby means of foils 4 and consists of the helically wound configurations5a to 5g, which are connected by means of intermediate members 6. Theconfigurations to Se, in the centre ofthe lamp envelope, are shorterthan the configurations 5a, b, f, g located on the sides. The shortconfigurations 5c to 5e are supported by the supports 7c to 72,respectively. The longer configurations 5a, 5b, 5f and 5g are eachsupported by two supports which are denoted by successively 7a, 7b, 7 fand 7g. The supports 7 consist of helically wound pieces of wire whicheach bear against the inner wall of the lamp envelope with an endportion. In the longer configurations 5a and 5g, present on the side ofthe pinches 2, the supports 7a and 7g are present between the centre andthe end of the configurations facing the adjoining pinch. These supportsmay, however, also be provided on the said ends of the configurations.According to the invention, the supports 70, 7b, 7f and 73 are providedat the ends of the associated configurations.

What is claimed is:

1. An electric filament lamp having a tubular envelope which' is sealedby pinches comprisng a filament which extends in the longitudinaldirection of the lamp, said filament consisting of a number of helicallywound configurations connected by straight intermediate members, thelength of the configurations which are present in the proximity of thepinches'being greater than the length of the configurations present inthe proximity of the center of the lamp, each of the longerconfigurations being supported by at least two supports and the shorterconfigurations by one support, each support comprising a centralaperture in which the relevant configuration is present, the outercircumference of said support bearing against the inside of theenvement.

* a a a 1:

mg UNITED STATES PATENT OFFIQE QERTENQATE 9F CQRREQTWN Patent No.3,759,3 7 I Dated lnventofls) Herbert Kamiel Maria. OP DE BEECK It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Cole 1, line 25, "pluse" should read -pulse-.,

Signed and sealed this 19th day of February 197A.

(SEAL) Attest:

EDWARD M.FLET0HER,JR. c. MARSHALL DANN Attesting Officer Commissioner.of Patents

1. An electric filament lamp having a tubular envelope which is sealedby pinches comprisng a filament which extends in the longitudinaldirection of the lamp, said filament consisting of a number of helicallywound configurations connected by straight intermediate members, thelength of the configurations which are present in the proximity of thepinches being greater than the length of the configurations present inthe proximity of the center of the lamp, each of the longerconfigurations being supported by at least two supports and the shorterconfigurations by one support, each support comprising a centralaperture in which the relevant configuration is present, the outercircumference of said support bearing against the inside of theenvelope, wherein the supports which are present between the supportsadjoining the pinches and which support the longer configurations areprovided at the ends of said longer configurations to prevent warping ofthe intermediate members duirng recrystallization of the filament.